Strategic delegation in a sequential model with multiple stages

We analyze strategic delegation in a Stackelberg model with an arbitrary number, n, of firms. We show that the n-1 last movers delegate their production decisions to managers whereas the first mover does not. Equilibrium incentive rates are increasing in the order with which managers select quantities. Letting u_i^* denote the equilibrium payoff of the firm whose manager moves in the i-th place, we show that u_n^*>u_{n-1}^*>...>u_2^*>u_1^*. We also compare the delegation outcome of our game with that of a Cournot oligopoly and show that the late (early) moving firms choose higher (lower) incentive rates than the Cournot firms.Comment: To appear in International Game Theory Review (IGTR), Vol. 13, No. 3 (2011) 1-1

Incident venous thromboembolic events in the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER)

<p>Background: Venous thromboembolic events (VTE), including deep venous thrombosis and pulmonary embolism, are common in older age. It has been suggested that statins might reduce the risk of VTE however positive results from studies of middle aged subjects may not be generalisable to elderly people. We aimed to determine the effect of pravastatin on incident VTE in older people; we also studied the impact of clinical and plasma risk variables.</p> <p>Methods: This study was an analysis of incident VTE using data from the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER), a randomized, double-blind, placebo-controlled trial of pravastatin in men and women aged 70-82. Mean follow-up was 3.2 years. Risk for VTE was examined in non-warfarin treated pravastatin (n = 2834) and placebo (n = 2865) patients using a Cox's proportional hazard model, and the impact of other risk factors assessed in a multivariate forward stepwise regression analysis. Baseline clinical characteristics, blood biochemistry and hematology variables, plasma levels of lipids and lipoproteins, and plasma markers of inflammation and adiposity were compared. Plasma markers of thrombosis and hemostasis were assessed in a nested case (n = 48) control (n = 93) study where the cohort was those participants, not on warfarin, for whom data were available.</p> <p>Results: There were 28 definite cases (1.0%) of incident VTE in the pravastatin group recipients and 20 cases (0.70%) in placebo recipients. Pravastatin did not reduce VTE in PROSPER compared to placebo [unadjusted hazard ratio (95% confidence interval) 1.42 (0.80, 2.52) p = 0.23]. Higher body mass index (BMI) [1.09 (1.02, 1.15) p = 0.0075], country [Scotland vs Netherlands 4.26 (1.00, 18.21) p = 0.050 and Ireland vs Netherlands 6.16 (1.46, 26.00) p = 0.013], lower systolic blood pressure [1.35 (1.03, 1.75) p = 0.027] and lower baseline Mini Mental State Examination (MMSE) score [1.19 (1.01, 1.41) p = 0.034] were associated with an increased risk of VTE, however only BMI, country and systolic blood pressure remained significant on multivariate analysis. In a nested case control study of definite VTE, plasma Factor VIII levels were associated with VTE [1.52 (1.01, 2.28), p = 0.044]. However no other measure of thrombosis and haemostasis was associated with increased risk of VTE.</p> <p>Conclusions: Pravastatin does not prevent VTE in elderly people at risk of vascular disease. Blood markers of haemostasis and inflammation are not strongly predictive of VTE in older age however BMI, country and lower systolic blood pressure are independently associated with VTE risk.</p&gt

The implementation of a Web-based Learning Environment concerning teachers' collaboration in the area of Fluids

In our work we developed and implemented a specially developed web-based distance learning course, addressed to in service primary teachers in Greece in the area of fluids. The course aims at enhancing participants' understanding of fluids and as well as their collaboration towards producing teaching learning materials for their pupils. Fluids is taught in primary schools, in several countries including Greece, in which pupils and teachers have alternative views and difficulties, in understanding basic ideas concerning pressure and buoyancy. We implemented a specific strategy, in order to promote asynchronous collaboration among participants and evaluated results by using Murphy`s quantitative content analysis model. During recent years, in the area of higher education, a great number of applications have used Web-based learning environments, in order to support distance learning courses and computer supported collaborative approaches, in learning and problem solving, in several areas. Computer-mediated communication can facilitate collaborative learning strategies and approaches, thus providing opportunities for virtual communities of learners to collaborate in ways that lead to shared understanding. Evaluating on-line collaborative learning interactions is a complex task due to the variety of elements and factors that take place and intervene, in the way a group of participants comes together to collaborate, in order to achieve a learning goal. In this context, we developed a web based teaching strategy aiming at enhancing participants' understanding of fluids and as well as their collaboration towards producing teaching learning materials for their pupils. In the present study, we report on the strategy and the collaborative activities of participating teachers. The sample of our study consisted of twenty four, (24), experienced primary teachers, who attended a two years in service program at the Department of Primary Education, University of Thessaloniki. In developing the course, first software for the Web based learning environment implementation was chosen and the open source software B.S.C.W. (Basic Support for Collaborative Work), has been chosen, because it is free for academic use,(http://bscw.gmd.de/ ). Second specially developed materials in the area of fluids were digitized and uploaded to the environment. Third based on data from two pilot studies, we designed a special mixed strategy in order to enhance teacher’s collaboration. In order to identify collaboration possibilities, among teachers, we carried out quantitative content analysis of their written dialogues, using the widely applied model of Murphy.It is characteristic that one hundred fifty seven messages (157), found in the phases "co-construct shared perspectives" and "building shared goals", constitute the two thirds of the total messages. This number seems to point out that participants, despite the high complexity of the scientific topic, successfully managed to co-construct shared perspectives and building shared goals, taking under consideration content knowledge. It is possible that enhancement of their understandings of pressure and buoyancy supplied before the collaborative phase of the strategy facilitated participants to reach the higher levels in Murphy’s' model. As a matter of fact achieving such levels in web based collaborative activities may not be taken for granted, (Murphy, 2004). In other words we consider that if content knowledge was insufficient, we might found postings only from the first two phases of Murphy`s model, (social interaction & articulating individual perspectives), perhaps as monologues.The production of twelve shared artefacts from all participants, considered as identification and completion of collaboration. That is also a key element therefore all participants reached that phase, without any withdraws. We consider that participants were helped to achieve such goal by being specifically guided on how to collaborate instead of being left to proceed without instruction in a learning situation for which they had little prior experience

Osteopoikilosis: Pain as a Presenting Symptom in Three Family Members

Osteopoikilosis is a rare asymptomatic sclerosing bony dysplasia of benign origin. It is usually found incidentally on radiological examinations. Familial occurrence indicates a genetic milieu with autosomal dominant pattern. Here, we present a case report of a young woman suffering from pelvic pain due to osteopoikilosis (OPK). The same disorder was later found in her son and daughter

Interactive Effects of Approach and Avoidance Job Crafting in Explaining Weekly Variations in Work Performance and Employability

Meta-analyses on job crafting reveal that while approach-oriented job crafting (e.g., increasing job resources or challenging job demands) relates positively to employee performance, avoidance-oriented job crafting (e.g., decreasing hindering job demands) has either non-significant or negative implications for employee functioning. However, the joint effects of approach and avoidance job crafting remain an underdeveloped area of research. We administered a three-week diary survey among 87 employees to test interaction effects of approach and avoidance job crafting on employee (other-referenced and past-referenced) work performance and employability. Results revealed that decreasing hindering job dem

Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe

Severe early onset preeclampsia: short and long term clinical, psychosocial and biochemical aspects

Preeclampsia is a pregnancy specific disorder commonly defined as de novo hypertension and proteinuria after 20 weeks gestational age. It occurs in approximately 3-5% of pregnancies and it is still a major cause of both foetal and maternal morbidity and mortality worldwide1. As extensive research has not yet elucidated the aetiology of preeclampsia, there are no rational preventive or therapeutic interventions available. The only rational treatment is delivery, which benefits the mother but is not in the interest of the foetus, if remote from term. Early onset preeclampsia (<32 weeks’ gestational age) occurs in less than 1% of pregnancies. It is, however often associated with maternal morbidity as the risk of progression to severe maternal disease is inversely related with gestational age at onset2. Resulting prematurity is therefore the main cause of neonatal mortality and morbidity in patients with severe preeclampsia3. Although the discussion is ongoing, perinatal survival is suggested to be increased in patients with preterm preeclampsia by expectant, non-interventional management. This temporising treatment option to lengthen pregnancy includes the use of antihypertensive medication to control hypertension, magnesium sulphate to prevent eclampsia and corticosteroids to enhance foetal lung maturity4. With optimal maternal haemodynamic status and reassuring foetal condition this results on average in an extension of 2 weeks. Prolongation of these pregnancies is a great challenge for clinicians to balance between potential maternal risks on one the eve hand and possible foetal benefits on the other. Clinical controversies regarding prolongation of preterm preeclamptic pregnancies still exist – also taking into account that preeclampsia is the leading cause of maternal mortality in the Netherlands5 - a debate which is even more pronounced in very preterm pregnancies with questionable foetal viability6-9. Do maternal risks of prolongation of these very early pregnancies outweigh the chances of neonatal survival? Counselling of women with very early onset preeclampsia not only comprises of knowledge of the outcome of those particular pregnancies, but also knowledge of outcomes of future pregnancies of these women is of major clinical importance. This thesis opens with a review of the literature on identifiable risk factors of preeclampsia